NASA managers request change to STS-125, STS-126 launch dates

July 16, 2008 by Chris Bergin

A CR (Change Request) has been issued to attempt to push forward the launch dates of STS-125 and STS-126. If approved, Atlantis’ trip to Hubble will take place NET (No Earlier Than) October 2, allowing Endeavour’s mission to the ISS to move up to November 4.

Meanwhile, Atlantis’ External Tank (ET-127) is now being processed in the checkout cell inside the Vehicle Assembly Building (VAB), following its barge journey from New Orleans.

The move, which is specific to handing margin to Endeavour’s STS-126 launch window – due to a Beta Angle Cutout that kicks in after November 25 – was initially set to be discussed at a Program Requirements Control Board (PRCB) meeting last week.

While the main PRCB meeting last Thursday was cancelled (due to lack of issues being worked with the fleet), it is not known if the decision was subsequently deferred, or approved in principle, with the CR document calling for a new decision date in August.

Titled ‘Update Launch Dates for STS-125 and STS-126’, Change Request documents are just that, requests for a change – to be discussed, approved, denied or modified as per feedback from all elements involved with the shuttle.

‘Increase launch opportunities for STS-126 before the Launch Beta angle cutout in November/December,’ was given as the specific reason for the CR.

The request calls for a change to the launch dates of STS-125 – advancing to October 2, STS-400 (Launch On Need) – advancing in sync to October 9 (if required), and STS-126 – advancing to November 4. UPDATE: Modification to STS-125 aims for October 5.

However, to approve the changes, several factors will come into play via the current timelines, notably the next two tanks (ET-129 and ET-130), and Atlantis’ payload, which is currently only just on the timeline to make the original – and current – launch date of October 8.

To allow for the launch date to advance from a payload standpoint, the Hubble servicing equipment needs to arrive at the Kennedy Space Center (KSC), from the Goddard Space Center, in time for September 11 – which is believed to reference the deadline for getting the payload to the pad.

Also required is ET-129 – which will be mated with Endeavour’s stack for the primary mission of STS-126, but in relation to Atlantis’ mission, it’ll be part of STS-400 – which will rollout to Pad 39B as the rescue shuttle. ET-129 currently has to be shipped no later than August 2.

Alternatively **CLICK HERE** For the free trailer for the 1,900mb L2 video of an exclusive tour of the VAB, OPF and Pad.

Another Michoud Assembly Facility (MAF) related element is the requirement for Endeavour’s STS-126 mission to have LON support. This relates to ET-130 – currently over a month behind schedule for Discovery’s primary mission of STS-119 in February.

‘STS-119 Remark: IS Rescue flight for STS-126 will be ready to launch on 2/2/09 with cargo element,’ added the CR presentation – available on L2 – as a requirement for the changes to be approved. This is an advancement of six days versus the current manifest.

All related elements will be reviewed at a PRCB meeting on August 14, allowing for a month of processing to refine the flow milestones – known as ‘critical paths’.

When the review takes place, several scenarios are available. Firstly, no changes to the current launch dates may be decided, if one or more critical paths is unable to support. All the changes could be approved, or managers could decide on STS-125 launching a few days earlier – rather than six days – allowing for STS-126 to gain a few additional opportunities in tandem.

External Tank Status:

With ET-127 now inside the VAB (Click image to view a timelapse movie of ET-127 VAB Ops), processing of STS-125 is closing in on another major milestone – ET/SRB (Solid Rocket Booster) mating.

The pre-mating review is set to take place on July 25, with the flow timelines showing mating is set to take place at the end of the month.

‘The ET was transferred to the VAB (1st motion at 2145 hrs EDT) and lifted to vertical early this morning. It was placed in the checkout cell later this morning with initial inspections to follow.’

Focus is now being placed on ET-129, with every day gained in the flow aiding the timeline to ship the tank in time to allow managers the option of advancing the launch targets.

This can be seen in a new production process which will debut with Endeavour’s tank. It’ll only save a day’s work on one element of tank production – but that could prove to be priceless in the bigger picture.

‘Relative to ET-127/ET-129 processing, Orbiter (Project Office) has a task utilizing a Boeing team to do work on the flapper valve on the ET disconnect,’ noted the latest Shuttle Stand-up/Integration report. ‘It’s Crit 1 function hardware added after Challenger to ensure the flapper valve doesn’t go closed.

‘Today, it takes at least 48 hours to do this work. (However,) they have pulled the community to try and find extra engineers and additional personnel to support this task in 24 hours. Can’t do this for ET-127, (but) for ET-129, they found a JSC engineer that works for Boeing who was once certified to do this task.

‘He will re-qualify for this and work with the Boeing team. For Steve Stich (newly promoted as new head of OPO), it’s a good example of the need for innovation in supporting tasks.’

ET-129 itself is currently being processed seven days a week at MAF, as they attempt to get the tank out of the door as close to the start of August as possible.

‘ET-129: Moved tank to Building 420, test and checkout cell. Activities are proceeding and are going well. Critical path runs through electrical/mechanical work,’ added Lockheed Martin’s status on tanks undergoing major production at MAF.

‘Cable tray gap closures, final routing and testing, vent valve splice and bonding are also in progress. LO2 feedline TPS (Thermal Protection System) closeouts proceeding this week as well as closeouts at bracket and other TPS closeouts on aft end. Crew came in this weekend and was able to make good progress.’

‘ET-130 (STS-119): Tank is in final assembly. Completed leveling. In process of installing platforms so can get to ice/frost ramp. Expect to start putting simulator in place at end of this week so can begin optics on aft interface hardware installation activities.

‘ET-131 (STS-127): Working through flange trims which are 95 percent complete. Completed all of LOX tank ice/frost ramp applications, and are now working on intertank ice/frost ramp applications. Have a few more applications to do before can move tank into Cell A.’

All three orbiters are enjoying a smooth flow in their respective OPFs (Orbiter Processing Facilities), with a full processing outline (daily on L2) to be published at the end of the week.

L2 members: All documentation – from which the above article has quoted snippets – is available in full in the related L2 sections, updated live.